U.S. patent application number 14/838065 was filed with the patent office on 2016-06-30 for method and device for positioning and stabilization of bony structures during maxillofacial surgery.
The applicant listed for this patent is Vito Del Deo, Xinsheng Cedric Yu. Invention is credited to Vito Del Deo, Xinsheng Cedric Yu.
Application Number | 20160183979 14/838065 |
Document ID | / |
Family ID | 56162903 |
Filed Date | 2016-06-30 |
United States Patent
Application |
20160183979 |
Kind Code |
A1 |
Del Deo; Vito ; et
al. |
June 30, 2016 |
METHOD AND DEVICE FOR POSITIONING AND STABILIZATION OF BONY
STRUCTURES DURING MAXILLOFACIAL SURGERY
Abstract
A maxillofacial or cranial-facial surgical stabilizer comprising
a head frame fully or partially surrounding the head of a patient
at an angle running from ears to temple, and that is fixated to the
skull of the patient by multiple screws and/or ear holders and
screws. One or more flexible/locking arms are removably attached to
the head frame for holding and positioning a plurality of
interchangeable instruments or accessories. One flexible/locking
arm is a medial/center arm accessorized with a dental arch mold. A
method of using a head frame to position the pieces of bones during
maxillofacial or cranio-facial surgery is also provided.
Inventors: |
Del Deo; Vito; (Forio,
IT) ; Yu; Xinsheng Cedric; (Pasadena, MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Del Deo; Vito
Yu; Xinsheng Cedric |
Forio
Pasadena |
MD |
IT
US |
|
|
Family ID: |
56162903 |
Appl. No.: |
14/838065 |
Filed: |
August 27, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62042500 |
Aug 27, 2014 |
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Current U.S.
Class: |
606/56 |
Current CPC
Class: |
A61B 90/14 20160201;
A61B 90/16 20160201; A61B 34/10 20160201; A61B 2034/107 20160201;
A61B 2034/104 20160201; A61B 90/57 20160201; A61B 17/8085 20130101;
A61B 2090/508 20160201 |
International
Class: |
A61B 17/62 20060101
A61B017/62; A61B 90/14 20060101 A61B090/14; A61B 34/10 20060101
A61B034/10 |
Claims
1. A maxilla/cranial-facial surgical stabilizer, comprising: a
metal frame configured to be fixated to a skull of a patient; a
flexible arm attached to said frame, said flexible arm protruding
from said frame to a distal end configured for removable attachment
of a medical instrument to support, orient and stabilize the
instrument.
2. The maxilla/cranial-facial surgical stabilizer according to
claim 1, further comprising a plurality of said flexible arms
attached to said frame.
3. The maxilla/cranial-facial surgical stabilizer according to
claim 1, wherein said flexible arm is attached to said frame by a
joint.
4. The maxilla/cranial-facial surgical stabilizer according to
claim 3, wherein said joint is translationally adjustable about
said frame.
5. The maxilla/cranial-facial surgical stabilizer according to
claim 1, further comprising a medial arm and two lateral arms.
6. The maxilla/cranial-facial surgical stabilizer according to
claim 1, wherein said flexible arm is selectively switched to a
rigid locked position.
7. The maxilla/cranial-facial surgical stabilizer according to
claim 1, wherein flexibility of said flexible arm is
user-variable.
8. The maxilla/cranial-facial surgical stabilizer according to
claim 1, wherein said flexible arm comprises a plurality of
ball-and-socket links.
9. The maxilla/cranial-facial surgical stabilizer according to
claim 1, wherein said head frame is substantially
horseshoe-shaped.
10. The maxilla/cranial-facial surgical stabilizer according to
claim 1, wherein said head frame comprises a plurality of sections
slidably attached together.
11. A maxilla/cranial-facial surgical stabilizer, comprising: a
head frame formed as a rigid ring at least partially encircling a
patient's head; at least one flexible locking arm comprising a
adjustable base joint at one end configured for releasable
attachment to said head frame, a mounting socket at another end, a
flexible arm extending between said base joint and said mounting
socket formed of a plurality of flexible locking joints, and a
tensioner mounted on said flexible arm for adjusting tension of
along said plurality of flexible locking joints; and a surgical
implement mounted in said socket.
12. The maxilla/cranial-facial surgical stabilizer according to
claim 11, wherein said adjustable joint is translationally
adjustable about said frame.
13. The maxilla/cranial-facial surgical stabilizer according to
claim 11, wherein said flexible arm is selectively switched to a
rigid locked position.
14. The maxilla/cranial-facial surgical stabilizer according to
claim 11, wherein flexibility of said flexible arm is
user-variable.
15. The maxilla/cranial-facial surgical stabilizer according to
claim 13, wherein said flexible arm comprises a plurality of
ball-and-socket links.
16. A method for performing maxillofacial surgery, comprising the
steps of: affixing a head frame formed as a rigid ring to a skull
of a patient so that said head frame at least partially encircles a
forefront of said patient's head at an angle running from ears to
temple, and fixating by screws; attaching a surgical implement to
one end of a flexible locking arm, said flexible arm comprising a
plurality of flexible locking joints and a tensioner mounted on
said flexible arm for adjusting tension along said plurality of
flexible locking joints; attaching another end of said flexible
locking arm to an adjustable base joint, which is mounted on the
said head frame; manually positioning said surgical implement
adjacent a mobile bony segment; manually adjusting said flexible
locking arm to position said mobile bony segment in a desired
position and orientation; locking or stiffening said flexible
locking arm in said desired position by increasing tension via said
tensioner; obtaining a radiological image of said mobile bony
segment in said desired position; analyzing said radiologic image
to verify said desired position; adjusting the position and
angulation of each arms based on the analyses of the radiologic
images is needed by using the adjustable base joint without
breaking the stiffened setup; and permanently fixing said mobile
bony segment in said desired position.
17. Method for maxilla/cranial-facial surgical treatment planning,
comprising the steps of: fixating a maxilla/cranial-facial surgical
stabilizer to a skull of a patient, said stabilizer comprising a
metal frame configured to be fixated to the skull and a flexible
arm attached to and protruding from said frame to a distal end
configured for removable attachment of a medical instrument;
attaching an implant to the distal end of said arm to support and
stabilize said implant; adjusting said arm to position said implant
in a fixed position and orientation; and verifying the fixed
position and orientation of said implant radiologically.
18. The method for maxilla/cranial-facial surgical treatment
planning according to claim 17, further comprising repeating said
adjusting and verifying steps multiple times.
19. The method for maxilla/cranial-facial surgical treatment
planning according to claim 18, followed by a step of fixating said
implant.
20. A system for surgical treatment planning, comprising: a
maxilla/cranial-facial surgical stabilizer including a metal frame
configured to be fixated to a skull of a patient, and a flexible
arm attached to said frame, said flexible arm protruding from said
frame to a distal end configured for removable attachment of a
mold; and a computer processor and software resident on
non-transitory computer readable storage medium at said processor
and comprising executable instructions stored on said computer
readable storage medium at said processor for verifying a position
and orientation of said mold radiologically.
21. The system for surgical treatment planning according to claim
20 wherein said maxilla/cranial-facial surgical stabilizer is
configured to provide a range of adjustable positioning and
orientation of said mold within a three axis frame of
reference.
22. The system for surgical treatment planning according to claim
21 wherein said range of adjustable positioning and orientation is
pre-programmed in said software.
23. The system for surgical treatment planning according to claim
22 wherein said software comprises image processing software for
imaging said mold.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present application derives priority from U.S.
provisional application Ser. No. 62/042,500 filed Aug. 27,
2014.
BACKGROUND OF THE INVENTION
[0002] (1) Field of the Invention
[0003] The present invention relates to maxillofacial surgery.
Specifically, it relates to stabilizers for positioning and
stabilizing fractured or surgically mobilized bony structures and,
more specifically, to a stabilizer for bony structures such as the
midface/maxillae and mandible for use in maxillofacial surgical
procedures.
[0004] (2) Description of Prior Art
[0005] Facial and mandibular bones may be broken up for surgical
purpose or accidentally in a traumatic injury. There are a variety
of cranio-facial procedures available for trauma and malformation
in which the broken bones are re-connected together to achieve both
function and cosmetic results. Currently, these procedures are
performed by surgeons and one or more surgical assistants. The
surgeon will manually position the bone to the best possible
alignment, and the broken pieces are then connected using metal
plates and screws. The conventional approach to positioning,
orienting, and stabilizing the unstable or mobile bone segments is
completely by hand, with minimal or no instrument assistance. The
examples of instrumental assistance including splits made with
dental castings. Such manual manipulation for finding the best fit
of the segments often requires several consecutive maneuvers in a
repetitive pattern, and can be challenging for the surgeon. At the
very least it diverts the surgeon's concentration, efforts and time
away from the procedure itself. This loss of focus can result in
suboptimal results, such as limited movement and facial dimensional
imbalance and/or asymmetry.
[0006] To aid the manual orientation, positioning and fixation
process, surgical planning systems were proposed. For example, U.S.
Pat. No. 7,792,341 to Filip Schutyser proposes a surgical planning
system that uses three-dimensional images of the patient to create
three-dimensional surfaces of structures in the maxillofacial
region and generate two-dimensional images (cephalograms). Such
image manipulation allows the analyses and planning of the
maxillofacial surgical procedures. The output from such
maxillofacial surgery planning system can be the parameters for
making plaster molds, making surgical splints, or to a computer
display that simulates the procedure as a means of navigating the
surgeon through the manipulation process (see, e.g., FIG. 13 and
FIG. 15 of U.S. Pat. No. 7,792,341). Although such planning is
useful in making the necessary molds and splints to aid the
procedure, it does not help in the actual manipulation process. It
also does not provide the guidance for fine tuning and adjustment
before fixation.
[0007] Ideally, the positional accuracy and the match to the
original geometry (in the case of a trauma) or the newly obtained
facial symmetry (in the case of a malformative syndrome) should be
established by standard anthropometric analysis using precise
anthropometric measuring tools, and then verified radiologically
prior to fixation with plates and screws. However, this is not
possible when the bone pieces are being held together by hand.
Similarly, surgical residents cannot learn the skills if they
cannot see the surgery because the surgeon is hovering over the
patient.
[0008] What is needed is a stabilizer device to make the procedure
less operator dependent, to allow objective verification of the
bone positioning and fine adjustment prior to fixation, and to
allow trainees in the room to view the positioning and orientations
of all bone pieces before they are screwed together.
[0009] Headframes for stereotactic neurosurgery and radiosurgery
are well known. These headframes are ring-shaped structures which
are mounted to the skull of a patient to provide a fixed reference
with respect to the patient's skull. A typical stereotactic head
frame is a halo affixed to a patient's skull (under anesthesia)
using pins or screws. The stereotactic frame may also act as a
guide for delivering various instruments such as a biopsy needle or
DBS leads or electrodes. FIGS. 1-3 are a front perspective view,
top view, and side view, respectively, of a prior art head frame as
shown in U.S. Pat. No. 7,925,328 to Urquhart et al. issued Apr. 12,
2011. The frame 1 is attached to a patient's skull with three
screws 2 fixed into the frontal outer cortical bone/outer layer.
Such devices offer accurate neurosurgical localization during
procedures such as stereotactic cranial biopsy and cranial surgery.
For example, for radiosurgery of intracranial lesions, a head frame
is used to localize the lesion and to position the lesion at the
center of the radiation focus. See, Leksell, L., "Cerebral
Radiosurgery. I. Gammathalmotomy In Two Cases Of Intractable Pain",
Acta chirurgica Scandinavica, vol. 134, p. 585-595; 31 (1968).
However, such head frames have not been suggested or used for
aiding maxillofacial or cranio-facial surgery. A common drawback of
the frames disclosed by Urquhart et al and Leksell is that these
frames cannot be adjusted to the head size and shape and they
interfere with the maxillofacial surgeon's work.
[0010] During maxillofacial trauma procedures and
orthognathic/malformative procedures, the positioning, orienting
and stabilizing (POS) of unstable/mobile bony segments are
performed manually by surgeons without instrumental aids. Such
maneuvers are often tiresome and time consuming. Human hands often
lack long-term consistency, stability and strength, and so clinical
results are often operator dependent. Other drawbacks of the
current practice include the infeasibility of position verification
before fixation, and the limited teaching/education capacity. These
are all factors that can interfere, affecting that final position
of the skeletal segment and leading to undesired results, such as
asymmetry and suboptimal chewing function.
[0011] In view of the foregoing, the present disclosure provides a
method and device for positioning and stabilization of bony
structures during maxillofacial surgery that improves clinical
performance of surgeons by freeing the surgeon's hands so that
two-dimensional or three dimensional radiological images can be
taken and verified against prior image sets and/or reference data.
It is also the objective of the present disclosure to allow very
fine adjustments to a stabilized arrangement of bony segments if
desired prior to bone fixation. The device frees the surgeon's
hands and makes their task less strenuous, more accurate, easier
and efficient. The device is specifically configured to stabilize
the mandible and/or the upper pallet for the purpose of
maxillofacial and cranio-facial surgery without interfering with
the procedure or anesthesia equipment.
SUMMARY OF THE INVENTION
[0012] Accordingly, it is an object of the present invention to
provide a maxillofacial surgical stabilizer capable of holding a
plurality of instruments in any desired position about the head,
and which allows repositioning of the instrument(s) quickly and
easily by single-handed manipulation.
[0013] It is another object to provide a maxillofacial surgical
stabilizer as above that provides full multidirectional
adjustability of the location of the desired instrument.
[0014] It is still another object to provide a maxillofacial
surgical stabilizer with the adjustability as above and yet which
can be selectively locked into position for rigid, reliable and
secure support of an instrument or instruments.
[0015] In accordance with the foregoing and other objects, the
present invention is a maxillofacial or cranial-facial surgical
stabilizer. The device comprises a metal frame that is fixated to
the skull of the patient with multiple screws, or a combination of
external ear holders and screws. On the frame, a plurality (minimum
one-maximum five) of flexible arms can be optionally attached and
interchangeably accessorized. These flexible arms can each be
stiffened by a tightening lever. At the free ends of the arms,
accessories such as dental molds, clamps and retractors can be
attached in a fashion as a surgical set-up splint that can be used
to replicate the planned position and also to support, orient and
stabilize the maxillae/upper jaw in relation to the skull. The
accuracy of the bony segments positioned and stabilized according
to the procedures and with the stabilizer disclosed above can now
be verified radiographically.
[0016] It is also the objective of the present disclosure to
provide a computer system to aid the anthropometric analysis. The
computer system is referred to as the anthropometric planning
system (APS). The radiographs can be manipulated and compared with
prior radiographs in the APS. The mandible can be rotated on the
APS screen to reveal any gaps or obstructions. The matching of the
upper and lower teeth can also be verified. The positions of all
bony segments can be fine-tuned virtually on the APS to reach their
ideal position. The required translations and rotations of each of
the arms to reach these ideal settings are calculated and displayed
and/or printed.
[0017] The APS of the present invention is specifically designed
for use in combination with the stabilizer of the invention.
Specifically, the APS is dedicated to the fine tuning of the
fixation arms of the present disclosure rather than planning the
molds or a splint as with prior art maxillofacial surgery planning
systems. Alternately, the APS may be used to provide a virtual
simulation of a procedure to navigate a manual procedure. Without
the stabilizer and the ability to make fine adjustments, the plan,
no matter how good, cannot be executed accurately. This way, the
output of the plan is not simply virtual images on a screen showing
how to put the bony segments together, but guided instructions
explaining to the operator which knob on which joint the stabilizer
arms is connected to turn, and by how many degrees, so that the
bony segments are perfectly aligned. The planning process is also
different: rather than operating on the bones, the present planning
system operates on the freedom offered by the adjustable base
joints.
[0018] To facilitate the required fine adjustments, the joint of
the flexible arm and the metal frame contains mechanisms to allow
the attached arm to make fine translational adjustments in all
three dimensions and to make fine rotational adjustments about one
or more axes. The availability and ranges of all forms of
adjustments are known to the APS so that the APS will only make
executable adjustments.
[0019] In view of the above, a method of using a head frame and
mechanical arms mounted on it to position the pieces of bones
during maxillofacial or cranio-facial surgery is also provided. The
method comprises i) attaching a head frame bearing one or more
mechanically-positionable arms to the skull of the patient; ii)
using a dental mold and/or other instruments (clamps, retractors,
etc.) held in the arms mounted on the metal frame to position,
orient and secure the upper jaw and additional bony pieces in their
optimal positions; iii) make further fine adjustment of the
stiffened arrangement by adjusting a joint positioning mechanism;
iv) verifying the correct positioning and orientation
radiologically; v) optionally, using the APS to make virtual
verification and adjustments to yield the required fine
adjustments; vi) make the fine adjustments required by the APS on
the joint positioning mechanism; and repeat steps iv) to vi) is
necessary; and vii) fixating the pieces with metal fixation
parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Other objects, features, and advantages of the present
invention will become more apparent from the following detailed
description of the preferred embodiments and certain modifications
thereof when taken together with the accompanying drawings in
which:
[0021] FIG. 1 is a front perspective view of a prior art head frame
attached to a patient's skull.
[0022] FIG. 2 is a top view of the prior art head frame of FIG.
1.
[0023] FIG. 3 is a side view of the prior art head frame of FIGS.
1-2.
[0024] FIG. 4a is a front perspective view of a maxillofacial
surgical stabilizer 2 according to the present invention.
[0025] FIG. 4b is a top view of the maxillofacial surgical
stabilizer 2 of FIG. 4a.
[0026] FIGS. 5a, 5b, and 5c are an anterior view, side view and
posterior view of an alternative embodiment of the frame that
completely encircles the patient's head.
[0027] FIG. 6 is an isolated perspective view of one of the
flexible locking-arms 22, 24, 26 used with the maxillofacial
surgical stabilizer 2 of FIGS. 4a and 4b.
[0028] FIG. 7 is a side view of the maxillofacial surgical
stabilizer 2 of FIGS. 4a and 4b illustrating its ergonomic
advantages and unobtrusive presence from a surgeon's
perspective.
[0029] FIG. 8 is a block diagram illustrating the steps involved in
using the maxillofacial surgical stabilizer 2 of FIGS. 4a and 4b
according to the method of the present invention.
[0030] FIG. 9 is a flowchart illustrating the detailed substeps of
the treatment planning phase of FIG. 8.
[0031] FIG. 10 is an exemplary joint 270 for attaching the flexible
locking-arms 22, 24, 26 to the surgical stabilizer 2 of FIGS. 4a
and 4b.
[0032] FIG. 11 is an alternate adjustable joint 275 for attaching
the flexible locking-arms 22, 24, 26 to the surgical stabilizer 2
of FIGS. 4a and 4b.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] The present invention is a stabilizer for bony structures
such as the midface/maxillae and mandible for use in maxillofacial
surgical procedures, and a method for use thereof.
[0034] With combined reference to FIGS. 4a and 4b, the present
invention is a maxillofacial surgical stabilizer 2 that is
specifically adapted for positioning and stabilizing fractured or
surgically mobilized bony structures such as the midface/maxillae
and mandible during maxillofacial surgical procedures. Generally,
stabilizer 2 comprises a light-weight rigid semi-circular head
frame 10 positioned about the forefront of the patient's head, and
one or more flexible locking-arms 22, 24, 26 each attached to the
head frame 10 via a joint 270 that allows translation and/or
adjustment relative to the head frame 10. Preferably, at least one
medial arm 22 is provided and two or more optional lateral arms 24,
26 all attached to the frame 10 via corresponding joint(s) 270. The
flexible locking-arms 22, 24, 26 are configured with distal
receptacles to releasably hold any of a variety of instruments,
implants or other accessories.
[0035] For example, as seen in FIG. 4b locking-arms 22, 24, 26 are
configured with distal molds. The medial/center arm 22 is
accessorized with a dental arch mold 32 that can be used to
replicate the planned position and also to support, orient and
stabilize the maxillae/upper jaw in relation to the skull. In the
illustrated embodiment three dental molds 32, 34, 36 are held in
place on the three flexible/locking arms 22, 24, 26. However, one
skilled in the art will understand that arms 22-26 may be used to
support other instruments, such retractor tools.
[0036] Head frame 10 is a horseshoe-shaped member comprising an
elongate arcuate member 12 formed from aluminum, titanium alloy or
other light weight composite material suitable for high-temperature
sterilization methods. Arcuate member 12 wraps around the front of
the head and a cross-piece 18 underlies the arcuate member 12 and
is adjustably screwed to the frame 10 at both ends as shown,
effectively bridging the frame 10 and providing a mounting for a
head screw 52. The distal ends of the cross-piece 18 are screwed to
the arcuate member 12 such that the cross-piece 18 forms a chord
across the semi-circular forefront of the frame 10. Thumb-screws 38
are used to secure the cross-piece 18 at each end. Optional
additional head screws 54, 56 may be provided as shown. In this
manner, the arcuate member 12 may be adjusted to properly space it
and thereby accommodate a range of acceptable head sizes, and then
affix it in position by tightening thumb-screws 38 and head screws
52, 54, 56.
[0037] The heels of the arcuate member 12 likewise include inwardly
directed tails 126, 146, said tails being formed as sockets for a
pair of adjustable ear plugs 42, 46. Ear plugs 42, 46 are mounted
on spring-biased screws to allow adjustment of the degree of
distension as well as their degree of spring-biased freedom of
movement. Ear plugs 42, 46 establish two fixed reference points by
centering inside the patient's ear canals. Three spring-biased
length-adjustable set screws 52, 54, 56 establish three additional
reference points: two at the patient's temples and one above the
bridge of the nose. Set screws 52, 54, 56 are adjustably threaded
through collars attached to the arcuate member 12. The head of the
set screws 52, 54, 55 is enlarged for finger-adjustment, and if
desired a spring may be mounted on the shaft of each of the screws
52, 54, 55 to pre-bias it.
[0038] One skilled in the art should understand that some other
combination of metallic pins/screws or external ear holders/plugs
may suffice, so long as the ears-to-temple orientation and fixation
is maintained.
[0039] In addition, head frame 10 can be modular. For example, FIG.
5 (A-C) illustrates an alternate embodiment of head frame 10 that
is modular and adjustable. Head frame 10 is in this case
constructed to encircle the patient's head completely with five (5)
parts as shown in FIG. 5 (A-C). For the ease of description, these
five pieces include a front right section 102, front left section
103, back right section 104, back left section 105, and the head
rest section 106. The five sections 102-106 may be joined
end-to-end as shown and may be configured with cooperating grooves
and rails as shown to slide together with a tongue-and-groove fit.
The sections 102-106 may be secured by set screw 108. Alternately,
the five sections 102-106 may slide together via a ratcheting
mechanism or the like. In either case the width of the head frame
10 can be adjusted to accommodate different sizes of heads through
the screws 108 and the sliding/ratcheting/adjustment mechanism. As
seen in FIG. 5(B) the two sections 102, 104 and 103, 105 at the
sides of the frame 10 on opposing sides of the patient's head are
substantially parallel. The height of the frame 10 relative to the
head can be adjusted by head screws 54, 56 (as shown in FIG. 4) to
accommodate different sizes of patient's heads. Ear plugs 110 can
be alternatively attached to the frame 10 and arch downwardly for
insertion in and stabilization against the ear orifices, thereby
ensuring that the left and right sides of the head frame 10 are
symmetrically placed around the patient's head. By inserting both
ear plugs 110 in the patient's ears, and adjusting the distance of
the ear plugs 110 to the lateral sections 102, 103 of the frame 10
to which they are attached, the patient's head can be perfectly
centered between the frame's left and right sides. The center head
rest section 106 also connects on both sides to the respective back
right section 104 and back left section 105 via a sliding mechanism
and screw(s) 108. The back right section 104 and back left section
105 are preferably bowed more in the back and turn straight on both
sides. Anywhere from four to six head screws 56 may be used to
secure the head frame 10 to the patient's head. Two screws are
preferably positioned one on the front of the patient and at least
two on the back. On each of the back right and back left sections
104, 105, two threaded holes are provided for screws 108.
Typically, only two screws 108 are needed on the back side to
secure the frame 10 onto the patient's skull. However, when the
patient's head is large or the patient has a thick scalp additional
screw holes can be used for added security. The frame 10 sits
tightly against the patient's head on the back side while the front
can have some space for the ease of arm attachments (not shown in
FIG. 5, see FIG. 4). After the frame 10 is secured on to the
patient's head, the two ear plugs 110 can be removed from the
patient's ears.
[0040] Referring back to FIG. 4, the flexible locking-arms 22, 24,
26 allow for easy single handed repositioning in any direction when
in an "unlocked" condition, yet maintain a secure fixed position
when in a "locked" condition, and with variable user-adjustable
resistance there between. All three flexible locking-arms 22, 24,
26 are identical.
[0041] FIG. 6 illustrates a presently-preferred flexible/locking
arm configuration which generally includes a yoke adapter 222 at
one end for pivotal connection to the arcuate member 12, and a
mounting receptacle 224 at the other end mounting a selected
mouthpiece 32, 34, 36 or any other desired surgical tool that needs
to be stabilized. The yoke adapter 222 is connected to the
receptacle 224 by an elongate series of locking flex-joints there
between. In the preferred embodiment the flex joints comprise
ball-and-socket links 230 with a tensioning cable 240 anchored to
receptacle 224 and running centrally through ball-and-socket links
230 to a tensioning fixture 250. Tensioning fixture 250 selectively
tensions or releases ball-and-socket links 230, thereby providing
an adjustable degree of flexibility of arms 22, 24, 26 ranging from
limp to rigidly locked in place. Tensioning fixture 250 further
comprises a rotary spindle 256 carrying a transverse handle 254.
Spindle 256 is rotatably journaled into a block 252 and turns a
sheave 258 carried in the block 252. An end of tensioning cable 240
is wound about the sheave 258. Thus, turning the handle 254 turns
the sheave 258 and tensions or untensions cable 240. Spindle 256 is
preferably ratcheted so that it cannot back up inadvertently, and
may be driven by a reduction gear to improve leverage.
[0042] The tensioning cable 240 may be any suitable twisted fiber
cord or cable. The cable 240 runs throughout the links 230 of the
arm 22 to tensioning fixture 250, which compresses the links 230
together to increase their collective rigidity, ultimately locking
them in position. There are a variety of alternative flexible arm
configurations that may suffice for present purposes, the primary
parameters being the ability to articulate mechanically in any
direction, mechanically freeze a desired position along its entire
length, and hold that position with maximum strength. The present
configuration does this with ball-and-socket links 230 configured
as shown in the inset to FIG. 6. A variety of different tools may
be attached at the ends of the two lateral flexible/locking arms
24, 26 for pushing and pulling, such as Langeback-like retractors,
partial/half/hemiarch splints, etc. The inset of FIG. 6 is an
enlarged illustration of an exemplary link 230 showing geometry.
Each link is a ball-and-socket design, with a convex face 233 at
one end and a concave face 231 at the other end. Each convex face
233 on one link conforms to the concave face 231 on the next
adjoining link, and so the ball-and-socket links 230 fit
end-to-end. Each link 230 is defined by an axial passage 234 for
passing the cable 240. The accuracy of the bony segments positioned
and stabilized according to the procedures and with the stabilizer
disclosed above can now be verified radiographically.
[0043] A computer system to aid the anthropometric analysis is also
optionally provided. The computer system is referred to as the
anthropometric planning system (APS). The radiographs, whether it
is two dimensional or three-dimensional, can be manipulated and
compared with prior radiographs in the APS. With three-dimensional
computer tomography images, the bony structures can be viewed from
all angles around the head, the mandible can be virtually rotated
on the APS screen to reveal any gaps or obstructions, and the
matching of the upper and lower teeth can also be verified. The
positions of all bony segments can be fine-tuned virtually on the
APS to reach their ideal position. The required translations and
rotations of each of the arms to reach these ideal positions and
angulations are calculated by the APS and displayed and/or
printed.
[0044] The flexible/locking arms 22, 24, 26 are each connected to
an adjustable joint 270 that is attached to the head frame 10 and
can make translational adjustments relative to the head frame 10.
The joint 270 itself also contains mechanisms to translate in
transverse plane and in the sagittal plane.
[0045] FIG. 10 is an exemplary joint 270 for attaching the flexible
locking-arms 22, 24, 26 to the surgical stabilizer 2 of FIGS. 4-5.
This exemplary joint 270 design has translational adjustment
capability (two-way) along arcuate member 12. The arm 22 passes
through joint 270 at a pivot joint (a bearing, bushing or the like)
and the arm 22 can also be rotated inside the joint 270. The arm 22
can be positioned and re-positioned laterally simply by loosening
one or more set screws 272.
[0046] FIG. 11 is an alternate adjustable joint 275 for attaching
the flexible locking-arms 22, 24, 26 to the surgical stabilizer 2
of FIGS. 4-5 and providing 4-dimensional adjustment capability
(three translations and one rotation). The arm 22 is secured
tightly inside a rod segment 272. The rod segment 272 is positioned
inside a channel in joint 270 and can slide up and down inside the
channel. The rod 274 is rotatably connected to a screw 276 at the
bottom. Turning the screw 276 will adjust the height of the rod 274
in the channel, which in turn moves that arm 22 in the direction of
the channel. The rod 274 can also be rotated inside the channel and
locked in position by a set screw (obscured). The joint 270 further
comprises three brackets 282, 284, 286 joined together by
orthogonal tongue and groove tracks to allow rod 274 to be moved
laterally both sideways and in superior--inferior direction by
turning the screw bars 288, 289 inside the top two "dove-tailed"
moving plates 286, 282 to cause the plates 282, 284, 286 to slide
in the desired direction. Additional adjustments in more rotational
dimensions can also be implemented. The provisions of such fine
adjustments of the positions of the flexible locking arms are
important. They allow the surgeon to achieve perfection from a
nearly perfect alignment of bony segments without loosening the
stiffened locking arms and start all over.
[0047] Because a small pivot of a bony segment may require a
complex combination of fine adjustments in multiple joints and in
multiple dimensions of each joint, it is impractical to compute the
required adjustments by hand. It is also too time consuming to make
such adjustments through a trial-and-error process. Therefore, a
computer system will generally be required to compute the needed
fine adjustments. The availability and ranges of all forms of
adjustments are known to the APS so that the APS will make
executable requirements. Also, when not in use, arms 22, 24, 26 may
be pushed away by releasing the tension in cable 240. By holding
all the links 230 in their optimal position based on the operators'
judgment, a radiological image can be obtained, and the positioning
can be verified against the patient's prior images on the APS
computer. The perfect bite between the upper and lower teeth can
also be verified by the virtual movement based on the radiograph on
the APS. If further finer adjustment is needed, the operator will
first make these virtual adjustments on the APS computer, which
will translate these adjustments to the actual knob-turning
instructions. The surgeon can then make these fine adjustments
using the adjustable joint without breaking the already stiffened
arrangement. Once the positioning is verified, the surgeon can take
his time to tie all the pieces together.
[0048] FIG. 7 is a side perspective view illustrating the geometry
of the maxillofacial surgical stabilizer 2 according to the present
invention, with head frame 10 attached to the patient's supporting
platform/operating bed to provide immobilization of the patient's
head relative to the patient support platform/operating bed if such
immobilization is desired. The combination of pins/screws, one
above the nose bridge and two at the temple, plus ear-plugs,
orients the flat head frame 10 along an ears-to-temple orientation
which is least obtrusive during maxillofacial surgery. The device
may provide: [0049] Support for the bony segments; [0050]
Retraction of soft tissues (fornix exposure); [0051] Positioning of
the segments; [0052] Stabilization of the segments while fixating
it.
[0053] Also provided is a method for accurately orienting and
positioning mobile bony fragments using the maxillofacial surgical
stabilizer 2 according to the present invention, to thereby
stabilize them prior to fixation with hardware such as metal plates
and screws.
[0054] FIG. 8 is a block diagram illustrating the steps involved in
using the maxillofacial surgical stabilizer 2 of FIGS. 4-5
according to the method of the present invention.
[0055] At step 100 the head frame 10 is affixed to the skull of the
patient by positioning the head frame 10 (fully or partially
surrounding the head of the patient) at an angle running from ears
to temple, and fixating by screws 52, 54, 56 and ear plugs 42,
46.
[0056] At step 200 the desired stabilizing fittings such as dental
molds 32, 34, 36 are attached distally to the receptacles at the
ends of the flexible/locking arms 22, 24, 26.
[0057] At step 300 flexible/locking arms 22, 24, 26 are attached to
the head frame 10.
[0058] At step 400 flexible/locking arms 22, 24, 26 are manually
positioned by the surgeon to move the mobile bony fragments to
their correct location and orientation.
[0059] At step 500 with mobile bony fragments to their correct
location and orientation, the flexible/locking arms 22, 24, 26 are
locked in position by tensioners 250. Thereby the mobile bony
fragments are stabilized at their desired locations with the
correct orientation.
[0060] At step 600 with mobile bony fragments stabilized in their
correct location and orientation by flexible/locking arms 22, 24,
26, the configuration is verified by radiological verification
before all bony segments are fixated with metallic hardware. This,
for example, may entail an X-ray, ultrasound, or computed
tomography (CT) scan, or as seen in the inset, magnetic resonance
imaging (MRI) to provide a planning image (see inset).
[0061] At step 700 a treatment planning phase is implemented using
image processing software in which reference indicia and bony
segments are identified on the image file to optimize alignment,
and the accuracy of the imaged alignment is verified (arms 22, 24,
26 repositioned as needed). For example, the surgeon may verify
position prior to fixation of both skeletal segments and hardware
in respect to a planned 3D orientation of upper and lower dental
arches in a preformed surgical wafer in the occlusal plane. This
step 700 may entail automated identification and translation of
pixel image data into 3D stereolithographic cadcam models. If
desired, the treatment planning step 700 may entail comparison of
the radiographs of the patient taken prior to the traumatic injury
or operation.
[0062] In a preferred embodiment treatment planning is carried out
using an automated anthropometric planning system (APS). Given the
fact that there may be multiple joints/adjustment screws 52, 54,
56, 250, each with multiple degrees of freedom, there are myriad
possible adjustments for achieving an optimum fit. It is not
feasible for an operator to figure out how to adjust the
knobs/screws/joints screws 52, 54, 56, 250 to create a perfect fit
by trial-and-error. Therefore, it is preferable to optimize the fit
using computer optimization. For this purpose the maxillofacial
surgical stabilizer 2 is provided with a plurality of
radiation-opaque markers 300 at predetermined locations. For
example, as shown in FIG. 5, five (5) radiographic markers 300 are
shown. Markers 300 appear as dark spots in radiographic images, and
the known relative spatial coordinates of the five markings may be
used to adjust and optimize the accuracy of the bony segments
positioned and stabilized with the stabilizer 2, and such positions
can be verified radiographically.
[0063] Reference is now made to FIG. 9, which is a flowchart
illustrating the detailed substeps of the treatment planning phase
of FIG. 8, with reference to the anthropometric planning system
(APS) of the present invention.
[0064] At step 710 with the maxillofacial surgical stabilizer 2
applied to a patient a planning image is taken, such as a CT
image.
[0065] At step 720 the relative mutual position of the markers 300
are determined from the planning image. Identification of the
markers 300 and their locations may be carried out automatically,
for example using conventional marker location software using
suitable marker-locating algorithms.
[0066] At step 730, on the basis of the relative mutual position of
the markers 300 it is possible to calculate the actual spatial
coordinates for each marker 300 (xn, yn, zn). The spatial
coordinates of markers 300 correspond to anatomical features (e.g.,
jaw alignment, bone segment placement, etc.) and/or surgical tool
placement (e.g., mold placement). Step 730 may be performed by a
conventional imaging workstation and the identified markers and
relative position data may be transferred (automatically or
manually) to a treatment planning workstation for subsequent
steps.
[0067] At Step 740 one or more clinical requirements are
determined. The clinical requirement (s) may be preset by a user.
For example, the user may be provided with jaw positioning options
(e.g., through a user interface), to set clinical parameters for
the treatment, including any tolerance threshold limits. The user
may be guided/restricted in the placement options and/or range of
values selectable as a threshold. For example, the user may be
presented with user interface including a 3D model of the jaw and
selection controls for selecting an optimum position and tolerance
threshold values from a predefined range of values. Of course, some
clinical requirement(s) may be predefined and stored in the system,
and any clinical requirement that is not specified by the user may
be assigned a predefined default value.
[0068] At Step 750 one or more adjustment parameters are calculated
as needed to satisfy the clinical requirement(s) based on the
spatial coordinates of markers 300. Calculation of the adjustment
parameter(s) may include determining one or more optimization
parameter(s) for optimum placement of anatomical features (e.g.,
jaw alignment, bone segment placement, etc.) and/or surgical tool
placement (e.g., mold placement. The adjustment parameters are
calculated using a predefined empirical rule/relationship, or
optimization algorithm. Because there is only one perfect fit, a
simple "greedy search" algorithm can be used. A greedy algorithm is
an algorithm that follows the problem solving heuristic of making
the locally optimal choice at each step with the hope of finding an
optimum solution. For example, an adjustment parameter may be
quantified by the lack of a gap width between two bony segments or
between the upper and lower teeth. The calculated adjustment
parameter will reflect a degree of adjustment necessary to
interpose a proper gap width between the two bony
segments/teeth.
[0069] At step 760, the adjustment parameters are automatically
translated by the treatment planning workstation into a
step-by-step user-guided interface for implementing the
optimization process. Again, there are myriad possible adjustments
and it is not practical for an operator to figure out how to adjust
the knobs/screws/joints screws 52, 54, 56, 250 by trial-and-error,
nor for the treatment planning workstation to calculate one perfect
adjustment. Therefore, the treatment planning system must rely on
computer optimization. At step 760 the step-by-step user-guided
interface may suggest one or more initial adjustments to begin
implementing the optimization process. The optimization algorithm
may randomly select a knob to turn along a randomly chosen
direction by a random number of degrees, optionally multiplied by
an exponential function of the number of adjustment tries. The
exponential function is sometimes referred to as the "cooling
speed", it ensures convergence (that the adjustments get smaller)
as the number of trials increases. One skilled in the art will
understand that other optimization algorithms, such as genetic
algorithms or gradient-descent; can also be used for finding the
adjustments needed to achieve a perfect fit.
[0070] At step 770 the operator implements the prescribed
adjustment, and a second planning image is taken.
[0071] At step 780 if the stabilizer 2 fit improves, the system
will accept the adjustment. If the fit is worse the optimizer will
not accept the adjustment.
[0072] At step 790 if the stabilizer 2 fit is fully optimized the
system ends the optimization procedure.
[0073] The above-described method improves clinical performance by
facilitating surgical planning and implementation. The presence of
the device 2 does not interfere with the maneuvering of the
surgeons or with anesthesia equipment because the frame remains
away from the area of interest. The device and method also provide
the ergonomic comfort for the assisting nurses and residents.
Indeed, from an educational stand point the method and device of
the invention provides an unobstructed panoramic view to assisting
residents to view and assist in the procedure. Thus the device can
be used to implement teaching strategies, thereby improving
education.
[0074] Therefore, having now fully set forth the preferred
embodiment and certain modifications of the concept underlying the
present invention, various other embodiments as well as certain
variations and modifications of the embodiments herein shown and
described will obviously occur to those skilled in the art upon
becoming familiar with said underlying concept. It is to be
understood, therefore, that the invention may be practiced
otherwise than as specifically set forth in the appended
claims.
* * * * *